#include<stdio.h>
char get_choice(void);
char get_frist(void);
int get_int(void);
void count(void);
int main(void)
{
    int choice;
    void count(void);
    while((choice = get_choice()) != 'q')
    {
        switch(choice)
        {
            case'a':printf("Buy low,sell high.\n");
            break;
            case'b':putchar('\n');
            break;
            case'c':count();
            break;
            default:printf("Proram error!\n");
            break;
        }
    }
    printf("Bye.\n");
    return 0;
}

void count(void)
{
    int n, i;
    printf("Count how far?Enter an integer:\n");
    n = get_int();
    for(i = 1;i<=n;i++)
    printf("%d\n",i);
    while(getchar()!='\n')
    continue;
}

char get_choice(void)
{
    int ch;
    printf("Enter the letter of your choice:\n");
    printf("a. advice          b.bell\n");
    printf("c. count           q.quit\n");
    ch = get_frist();
    while((ch < 'a' || ch > 'c') && ch != 'q')
    {
        printf("Please respond with a,b,c,or q.\n");
        ch = get_frist();
    }
    return ch;
}

char get_frist(void)
{
    int ch;
    ch = getchar();
    while(getchar()!='\n')
    continue;
    return ch;
}

int get_int(void)
{
    int input;
    char ch;
    while(scanf("%d",&input) != 1)
    {
        while((ch = getchar()) != '\n')
        putchar(ch);
    printf(" is not an integer.\nPlease enter an ");
    printf("integer value,such as25,-178,or 3: ");
    }
    return input;
}





